18-07-2012, 12:39 PM
OVER VIEW OF LANCO POWER STATION
OVER VIEW OF LANCO POWER.pptx (Size: 2.85 MB / Downloads: 37)
Explanation:-
The power produced by the three units of 120MW each.
This supplies to the grid through kp1,kp2,kp3,Gudivada,Chillakallu and spare is provided for the purpose of extension.
Turbine 1 & gas turbine 2 are passed to HRSG & steam is generated in HRSG at 3 levels HP,LP,IP will be fed to S.T.
They are two step down T/F’s 15 kv /6.6kv which are fed to GTG1>G2 these are called unit T/F’s UT1 & UT2 feeds to unit switch gear bus.
There 2 more step down T/F’s 220KV/6.6KV , the main purpose of this station bus bar system is to start the plant by taking supply from the grid and this bus also feeds our auxiliaries like station service MCC, switchyard ACDB.
The LANCO POWER PLANT consists of following equipments:
0. Fuel system
1. steam turbine generator
2. Heat recovery steam generator
3. Gas turbine genarator
4. steam condensing system
5. De-Mineralizing plant
6. Automatic high velocity sprinkle system
7. Switch yard equipment
Fuel System
Types of fuels used :
1. Natural Gas(GAIL-GAS)
2. NAPTHA
3.High Speed Diesel
The main fuel is natural gas and the liquid fuel is either Naptha or HSD is used in case of deficiency of natural gas supply.
Naptha is stored in two large tanks of capacity 19,000kl. Each tank can store fuel required to run entire power plant continuously for 3 days . This liquid is highly volatile.
HSD will pump the fuel from long lorry to storage tanks. The tanks are built up of cast steel by ASTM.These are also two-in-one. One is untreated oil storage tank oter is treated oil storage tank. Capacity of 1500kL.
operation(Gas Turbine Generator):-
Gases passing through an ideal gas turbine undergo three thermodynamic processes. These are isentropic compression, isobaric (constant pressure) combustion and isentropic expansion. Together these make up the Brayton cycle.
Gas turbine is used as operating medium in the process.
In this the air is drawn from the atmosphere and it sends in to the compressor chamber after that the compressed air is filtered and passed through the combustion chamber for heat addition.
The exhaust gas temp. from the turbine exit is used in HRSG before exhausting in to the atmosphere.
Heat Recovery System Generators:-
HRSGs consist of Four major components: the Economizer, Evaporator, Superheater and Water preheater. The different components are put together to meet the operating requirements of the unit. See the attached illustration of a Modular HRSG General Arrangement.
HRSG consists of mainly three modes :
Low pressure(LP)
High Pressure (HP)
Intermediate pressure (IP)
Steam turbine :-
A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion.
The steam after expansion in turbine is exhaust to the gland steam condenser via condensate extration pump.
De Mineralizing plant
Demineralization or D.M. plants help to remove dissolved minerals from water to make it suitable for industrial and municipal use. In exchange and electrically driven membrane are the major methods for deionizing water. The process involves purifying water by filtering it through a tank containing beads of synthetic resin.
These beads are chemically treated to either absorb negatively charged anions or positively charged cations.
Time-graded over current protection
In this scheme of over current protection, time discrimination is incorporated i.e. the time setting of relays is so graded that in the event of fault, the smallest possible part of the system is isolated.
Time-graded protection of a radial feeder can be achieved by using Definite time relays and Inverse time relays
Over current protection of radial feeder by definite time relays
The time of operation of each relay is fixed and is independent of the operating current. Relay D has an operating time of 0.5 second while for other relays, time delay is successively increased by 0.5 second. If a fault occurs in the section DE, it will be cleared in 0.5 second by the relay and breaker at D because all other relays have higher operating time.
The disadvantage of this system is that if there are a number of feeders in series, the tripping time for faults near the supply end becomes high.
Over current protection of parallel feeder
In parallel feeder system, instead of one feeder, there are two feeders which feed the substation in parallel. When continuity of supply is particularly necessary, parallel feeder system is employed. If fault occurs on one feeder, it can be disconnected from the system and continuity of supply can be maintained from the other feeder.
The parallel feeders cannot be protected by non-directional over current relays only. It is necessary to use directional relays also and to grade the time setting of relays for selective tripping.
CIRCUIT BREAKERS
Circuit breaker is automatic switching device which can
carrying normal current and switching in & out normal loads
Interrupt short circuiting currents
Able to performer auto reclose duty.
Classification of Circuit breaker:
Based on VOLTAGE
Low-less than 1kv
Medium-1kv to 52kv
High/Extra High-66kv to 765kv
Ultra High-above 765kv